By way of example, a joint with an adjustable angle is also disclosed in DE 196 06 092 A1 and it is used, for example, in ortheses for different body parts. The two joint arms are provided with holes in the region at which they abut. The holes of the one joint arm and the holes of the second joint arm overlay at certain values of the spread angle included by the two joint arms. In this case, the two pivot arms are interconnected by sticking a pin through the two overlaying holes and the joint is locked. If the pin is removed, the two joint arms can pivot with respect to one another without restrictions.
The pin can also be inserted into holes provided in only one joint arm. In the region of these holes, the other joint arm has a smaller radius from the pivot axis and comprises a stop lug. Said lug butts against the pin at a stop angle determined by the pin. This restricts the possible pivot angle in one direction.
The use of such joints in ortheses for e.g. the knee or elbow allows the corresponding body limbs to be fixed relative to one another in a certain position. The body joint cannot be moved if the orthesis joint is locked. However, the patient finds it practical and more comfortable to be able to pivot the orthesis joint into the desired position for attaching the orthesis.
It is disadvantageous that the locking can only be brought about at certain angular distances and that intermediate settings are not possible. Additionally, the locking procedure itself is also cumbersome and impractical. When the orthesis is applied, the two holes in the joint arms that should be connected by the pin have to be brought into an overlaid position. Additionally, it is difficult to recognize which angle is the correct angle at which the joint should be locked. Therefore, locking can be brought about at the wrong angles.
If the pin is pulled out of the joint in order to reach the release position from the locking position or the angle-limiting position, information relating to the previously set angle is lost. Said angle must, in the case where the joint should again be brought into the locking or angle-limiting position, be set in a cumbersome fashion by inserting the pin into the corresponding hole.
DE 199 04 554 A1 discloses a joint, in which the angular range, through which the first joint arm can be pivoted with respect to the second joint arm, can be set in a step-free fashion. For this, provision is made for two disks, which are connected to a joint arm in a rotationally secure fashion and each have an arc-shaped slot. A transverse pin that engages into the two slots is attached to the other joint arm. The two disks can be displaced with respect to one another by rotation about the pivot axis of the joint. This changes the region in which both slits are overlaid and in which the transverse pin, and hence the other joint arm, moves.
It is disadvantageous that the joint described in said document cannot simply be brought into a locking position or a release position. For this, the disks have to be displaced against one another in such a way that the region of overlay of the two slots is minimal or maximal. Since the disks are displaced by rotating a worm engaging in teeth provided on the disk, this change is cumbersome and long-winded. Moreover, information relating to the previously set angular range is also lost in this case.
DE 199 33 197 discloses a joint in which the two joint arms can be pivoted against one another over an adjustable angular region. For this, holes are provided in plates at intervals of in each case 15°, and stop elements can be inserted into said holes. This can be brought about in both pivot directions, and so the possible pivot region is restricted in both directions by the stop elements. The angle between the two stop surfaces, which butt against the respective stop elements, can only be adjusted in a step-free fashion over a region of 15°. This affords the possibility of adjusting, in a step-free fashion, the pivot region in which the two joint arms can be pivoted relative to one another.
The two joint arms can only be locked by selecting the pivot region such that the stop surfaces butt against the respective stop elements on both sides. It follows that the two joint arms can only be locked relative to one another at intervals of in each case 15°.